Wearables Need Tailored SoCs

SANTA CLARA, Calif. -- Wearables won't go mainstream until they get tailor-made silicon, according to a panel at the Linley Tech Mobile Conference here. The nascent market needs clearly defined use cases and SoCs geared for lower battery life, they said.

“We need to figure out a way to build a more engaging model. To be successful you need the right use case and battery life will be important. Wearables also have to be easy to use and compatible with other devices,” said Linley Group principal analyst Linley Gwennap.

Many wearables may be looked at as fashion accessories where bulkiness and the need to charge more than once a month become prohibitive. Users want their wearable devices -- from FitBits to Google Glass and home medical devices -- to be sleek, constantly connected through WiFi or Bluetooth, always on, and with an ultra long battery life, he said.

“People don’t buy specs when it comes to battery life, they buy behavior,” said Pankaj Kedia, a senior director of product management at Qualcomm. “It’s not enough to say low power, you have to define ambient and active modes. But if the thing doesn’t last, you’re dead; many users want the device to last a week, a month.”

Much of the issue around battery life stems from a device’s hardware components. Many chips are scaled down versions of handset SoCs, which have different processing requirements than a smartwatch or fitness tracker.

“Smartphone SoCs have different design goals -- do we really need that much performance in a wearable,” questioned Kurt Shuler, vice president of marketing for Arteris, a provider of SoC interconnects. “We’re starting to see SoCs designed for specific targets... Using clocked down SoCs designed for smartphones compromises battery life; a new computing architecture is necessary to fit the ultra low power requirement.”

Optimized hardware is key to a long-lasting battery which should be between 200-300 milliamp hours (mAH) for fitness bands and 300-500mAH for smartwatches. Instead of using multicore CPUs designed for smartphones, wearables could use multiple low power CPUs with frequencies under 300 MHz. Devices that don’t run apps can also forgo a graphics core because of small screen sizes, panelists said.

“Picking and choosing the right performance blocks will be important based on the segment you're targeting,” Kedia said. “In [always on, targeted experience] devices, the GPU matters less, if at all, and signal processing is most important.”

Choosing the right hardware stack and method of heat dissipation will also be among the key ingredients in a successful wearable, which shouldn’t get hot with regular wear, they said.

However, the sensors often in wearables are already present in smartphones, begging the question of where wearables will fit in a user’s device ecosystem. Finding use cases and proper hardware might be done more quickly in medical, industrial, and military spheres rather than for consumer products, Shuler said.

“Wearables will not save the semiconductor industry. This is the evolution rather than the revolution. This tech is an extension of where we’ve already been going with hardware and software,” Shuler said.

I would think that considerable energy savings could be achieved by having the device active only when the user is engaging with it. Much of the time the device could be in a sleeping mode awaiting incoming data or user input. If the device isn't being worn, it could be in an even deeper sleep mode. Still, there needs to be a recharging plan. Will the devices operate on a long life battery (like an electric watch) or will they have some mechanism to recharge overnight when not in use like a cell phone?

Very good point @_hm...but how do we tap to the energu we consume via food?...I remember readng about glucose harvesters, but by definition they need to get implanted somewhere in your body and get the energy out from there, not a pleasant solution even if it works...the most simple is to tap to the temperature difference between the body and environment but this only works in cold climate or air conditioned rooms...Kris

No reason why movement/kinetic energy cannot replace a battery, or keep a battery or supercap charged. Your point is valid, I was agreeing with you. But also pointing out that such energy harvesting is a proven technology that has been used for a long time and therefore would most certainly be viable in today's applications.